Telephone system



March 9, 1937. A, J;PAR,Ss| 2,673,586

TELEPHONE SYSTEM Filed Nov. 27, 1935 Patented Mar. 9, 1937 UNITED STATESPATENT OFFICE Anthony J. Parlssi, Gohoes, N. Y.

Application November 27, 1935, Serial No. 51,733

22 Claims.-

My invention relates to the signaling or annunciator phase ofcommunicating systems and thefundamental circuits embodied therein aregenerally similar to those disclosed in my copending application Ser.No. 701,747 which was -filed in the Patent Ofiice on or about the 11thday of December, 1933.

My invention more particularly relates to the association with atelephone circuit of an electric circuit having a separate source ofenergy and including a visual signaling device which, through the meansassociating the two circuits,

is operated in a predetermined manner when a signaling current energizesthe telephone circuit.

5 In view of the fact that the visual signaling circuit is dependentupon a. source of energy separate from that feeding the telephonecircuit and in order to insure continuity of service, that is, theemission oi. a signal of one character or another when the telephonesignaling circuit is energized, my invention has for a first object theprovision of means for efiecting an operation of the annunciator in thetelephone circuit in the event of a failure of the visual signal or thefailure of '25 power in its circuit.

Obviously, a visual signaling device is provided in order that anoiseless signal may be emitted at, for example, a subscribers stationin a telephone system where quietness is desirable. In some instances,circumstances may require intermittent absences of a person from view ofthe visual signal and, in such a case, it is desirable that an audiblesignal be given in the event that the visual signal is not answeredwithin a predetermined interval of time. My invention, therefore, hasfor another object the provision of means for effecting in response toan energization of the telephone circuit, first, the emission of avisual signal and secondly, after a predetermined time interval ofoperation thereof, the emission of an audible signal.

Inasmuch as I preferably use an incandescent lamp as the visualsignaling device in circuit in a commercial lighting system, myinvention contemplates, for a further object, the provision, incombination with a lamp andswitch of a current intermitting device andcircuit controlling means operable in response to an energization of atelephone signaling circuit whereby, normally, the lamp may be switchedon or oil? for ordinary illuminating purposes, but upon an energizationof the telephone circuit, the normal operation of the lamp isinterrupted and a flashing operation thereof occurs.

5 My invention has for further objects the provision of means formaintaining the signaling operation of the lamp after an initial flow ofsignaling current in the telephone circuit, means for determining themaintained lamp operation after a predetermined time interval ofoperation thereof and means for discontinuing the signal emission whenthe talking circuit is completed at the subscribers station. I

A still further object resides in the provision of a manual controlwhereby either the visual or the audible signaling device may beselected and operatively connected for use, or both signaling devicesmay be connected to operate simultaneously. 1

With these and other objects in view, my invention includes the novelelements and the combinations and arrangements thereof described belowand illustrated in the accompanying drawing in which- Fig. 1 is a wiringdiagram of my invention in its preferred form; and

Fig. 2 is a perspective view of a motor operated switch representativeof one of the elements incorporated in my device.

Referring to Fig. 1, I indicates an incandescent lamp connected betweenthe legs 2 and 3 of an electric lighting circuit, a switch 4 beinginterposed in the leg 3. The plug 5 and socket 6 constitute an optionalelement which lends flexibility to my device and are illustrated merelyto show a manner in which various lamps or a circuit comprising aplurality of lamps may be connected to the circuit comprisingthe-control devices of my invention. Hence, inasmuch as the lamp I maybe connected directly in circuit and the legs 2 and 3 and the third legor conductor 1, which is connected at one end to leg 3 intermediate theswitch 4 and lamp I, are electrically connected through the plug andsocket to three connecting, electrical conductors, I have designated thelatter by the same reference characters as the conductors to which theyare connected.

Leg 2 constitutes the common return conductor of the lamp circuit and isconnected to one main line 8 of the electric lighting service mains 8and 9. Leg 3 is connected to a contact ill of a relay ll, one armaturel2 of which in its normal position, that is, when the coil of the relayis unenergized, engages said contact and closes a circuit from leg 3 toconductor l3 to which said armature is connected. Conductor I3 is inturn connected to the main line 9 of the service. This circuit throughlegs 2 and 3 to lamp I may be termed the normal lighting circuit.

For simplicity of illustration, I have shown the relay I I as composedof four armatures. Obviously, a single armature having insulatedsegments adapted to engage the respective contacts and to perform thesame function as those illustrated may be employed.

A second armature H which is also connected to conductor I3 is, upon anenergization of relay adapted to engage contact l5 to which one terminall8 of a current intermitting device, indicated generally at H isconnected through conductor l8. The other terminal IQ of the device I1is in turn connected to conductor 1.

The current intermitting device may constitute what is commerciallytermed a flasher button. Obviously, any suitable means may-be employedwhich will produce a desired operation of the incandescent lamp whichdiffers from its normal one. The device H, which is illustrateddiagrammatically for descriptive purposes, comprises a fixed contact 2|)and'a movable contact 2|. Contact 20 is electrically connected withterminal l9 and contact 2| is in electrical contact with and supportedon a bimetallic element 22 which is secured at one end to the terminall6. A wire 23 of suitable ohmic resistance is coiled about thebimetallic element and electrically connected between the terminals l8and I9. Wire 23 is, therefore, connected directly in series withconductors 1 and I8. When the relay closes the lamp circuit through itsarmature l4, current flows through wire 23, it being in series with thefilament of lamp Wire 23 is designed to generate and radiate suflicientheat to cause the bimetallic element 22 to warp toward terminal l9,whereupon contacts 20 and 2| will touch, causing the resistance element23 to be shunted by the bimetallic element itself. The current flowthrough the wire 23 is not sufficient to illuminate lamp l but, upon theengagement of contacts 29 and 2|, the lamp is connected directly acrossthe mains 8 and 9 and beomes fully illuminated. This direct circuit tothe lamp is maintained until contacts 20 and 2| are disengaged due tothe cooling and retraction of the bimetallic element towards its normalposition. Obviously, during the maintenance of this circuit, the abovedescribed cycle of operations of the device |1 continues causing anintermittent illumination of the lamp From the foregoing, it is apparentthat an energization f the relay among other funcductor 28 to leg 2 ofthe lamp circuit andthrough conductor 29 to one contact 30 of a relay3|. The armature 32 of the relay 3| is adapted to engage contact 39 anda secondcontact 33 electrically to connect said contacts, contact '33being connected through conductor 34 to conductor l3.

It will be noted that the elements of my invention; described in theforegoing, with the exception of relay 3| are connected or areconnectible in circuit with the mains 8 and 9. These mains havehereinbefore been designated as electric lighting service mains.Obviously, any suitable source of power may be employed to which themains 8 and 9 are connected but, inasmuch as my invention, in itspreferred form, contemplates the normal use of lamp for ordinaryilluminating provided and the circuit arranged accordingly, I-

have designated conductors 8 and 9 as service mains with theunderstanding that they are connected to a commercial lightingdistribution system.

The relay 3|, however, is connected in circuit at the subscribersstation of a telephone system and is adapted to be operated in responseto an energization or flow of signaling current in said telephonecircuit. The subscribers station of the telephone circuit isdiagrammatically illustrated as comprising the terminals 35, 35, 31 and38 which comprise the points of connection between the usual telephonecircuit and trunk lines and the circuit embodying my invention. Thetelephone trunk lines, indicated at 39 and 40, are connected toterminals 39' and 31, respectively, 36. The terminals 4| and 42 areprovided for connection with the subscriber's telephone set and adetailed description thereof will not be entered into at this point. Oneterminal of the usual bell or audible signaling device 43 is connectedthrough a condenser 44 to terminal 39' and the trunk line 39 and theother terminal thereof is connected to terminal 38. A conductor 45connects terminal 38 to two contacts 45 and 41 of a manually operableswitch, indicated generally at 48.

Switch 48 is interposed in the bell circuit so that the subscriber mayselect and connect either the bell or the relay 3| in the telephonesignaling circuit. In other words, the subscriber may se lect either thevisual or lamp flashing signal, or, the audible or bell signal. At thesame time, the switch 48 is preferably constructed, as illustrated, alsoto connect both types. of signaling devices in circuit for simultaneousoperation.

The switch blade 49 of switch 48 is connected through conductor 59 tothe trunk line 48. Hence, when blade 49 engages contact 45 or 41 thebell 43 is connected directly across the trunk lines 39 and 40. On theother hand, when blade 49 engages a third contact of switch 48, the bellis disconnected and a new circuit created. One side of this new circuitincludes conductor 52 which connects said contact 5| with a movablecontact arm 53 of a two-position, motoroperated, switch indicatedgenerally at 54, which will be hereinafter described, and conductor 55which connects relay 3| through condenser 58 to one contact 51 of themotor-operated switch 54. The other side of this circuit comprisesconductor 58 which connects the relay 3| to the telephone line 39.

Assuming for the moment that the circuit is completed through contactarm 53 and contact 51 of the motor-operated switch 54 as shown, it willbe seen that switch 48 serves to connect either the bell 43 or the relay3| across the telephone trunk lines 39 ,and 48. Switch 48. however, isalso preferably designed to connect both the bell and the relay 3|across the trunk lines 39 and 49 so that a simultaneous operation ofboth will occur. For this purpose, the contact 41 and a fourth contact59 are provided, contact 41 being connected, as above described, toconductor 45 and contact 59 being connected to conductor 52. It will beevident, therefore, that when contact arm 49 is turned to engage.contacts 41 and 59, the bell 43 and relay 3| will both be connectedacross the telephone trunk lines.

, Inasmuch as my invention contemplates the provision of means foreffecting the emission of terminal 39' being connected to terminal avisual signal, let us assume that arm 49 of switch 48 is in engagementwith contact 5| and the telephone trunk lines 39 and 40 are energized.Signaling current flows from line 40 and terminal 31 through conductor50, arm 49 and contact 5| of switch 48 and through conductor 52.to arm53 ofmotor-operated switch 54. Further assuming that arm 53 lies in theposition'illustrated in engagement with contact 51, current flowstherethrough and through conductor 55 and con- Y denser 56 to relay 3|and thence through conductor 58 to terminal 36 of the other trunk line39. Hence, relay 3| is energized and the armamm 32 thereof is picked upforming an electrical connection between the contacts 30 and 33 therebyconnecting the primary 21 of transformer 26 across the electric servicemains 8 and 9. The transformer primary circuit may be traced as follows.One terminal of the primary winding is connected through conductor 28 toconductor 2 which is in turn connected to line 8 of the mains and theother terminal of the primary winding is connected through conductor 29vto contact 30, of relay 3|, through the armature thereof to contact 33,and thence through conductor 34 to conductor l3 which is connected toline 9 of the service mains. nected across the service mains, currentflows through its secondary circuit which includes the relay andconductors 2'4 and 24 and the armatures |2 and M of said relay areattracted by the pole piece to a position opposite to that illustrated.Hence, the connection of the primary of transformer 26 across the mains8 and 9 effects, through an operation of relay I, a discontinuance orinterruption of the normal lighting circuit through leg 3 andsubstitutes therefor the third leg which includes conductor 1, currentintermitting device I! and conductor l8.

From the foregoing, it is apparent that, assuming the switch 48 andmotor-operated switch 54 are in the positions illustrated, anenergization or flow of signaling current in the telephone trunk lines39 and 40 will effect an interruption of the normal lighting circuit andthe creation of a second circuit including the device I1 and theincandescent lamp The conductor 1, device l1 and conductor l8 form, ineffect, a shunt circuit around the switch 4 which is disposed in thedevice I1 is connected in series with the lamp and across the servicemains.

The above described operation of my invention illustrates the resultsobtainable with the fundatherefor, an intermittent illumination thereofoccurs as a flashing, visual signal when the telephone circuit isenergized. However, it is desirable that the visual signal be emittedfor a period of time exceeding the duration of the telephone signal andthat such period of time be limited to a predetermined interval in theevent the When the transformer 26 is consignal is not answered.Furthermore, it is desirable to automatically cut off the visual signalwhen the telephone talking circuit is opened and means, as hereinafterdescribed, are provided to attain these objects.

A very important feature, however, of my invention resides in the meanswhich I have employed to insure continuity of service or, in other wordsthe emission of one signal in the event of a failure of the other. Dueto the fact that the visual signaling device or incandescent lamp isdependent upon a source of electrical supply separate. from thatsupplying the telephone lines, I have provided a means, hereinbeforereferred to as a motor-operated switch 54, which is adapted to connectthe bell in the telephone circuit in the event of a power failure in thelighting circuit or the 'inoperativeness of the incandescent lamp. Ashereinbefore described, the movablc contact arm 53 of switch 54 when inengagement with contact 51 connects the relay 3| in the telephonecircuit assuming, of course, the arm of switch 48 is in the positionillustrated. The arm 53, as diagrammatically illustrated, is operated bya motor 60 which is connected to and receives energy from the lightingservice mains. Assuming upon energization of the motor its shaft rotatesclockwise, a projection 6| on the rotor shaft'urges the arm 53 inengagement with contact 51. It is to be understood that the rotor ofmotor 60 is designed to return to a predetermined positionwhenunenergized and in such position permits arm 53 to engage a contact 62.In other words, the rotor has a fixed, unenergized position and isdesigned, upon energization, toproduce a predetermined torque sufficientmerelyto urge arm 53 against contact 51. The contact 62 is connected byconductor 63 to conductor 45. Hence, when motor 60 is unenergized, thecircuit to relay 3| is opened and the bell is connected across thetelephone lines 39 and 40.

The motor-operated switch 54 is illustrated in greater detail in Fig. 2and the arm 53 and projection 6| are therein shown-as combined in theform of a contact arm 53' which is secured to and movable by the motorshaft 60I. Arm.53' is shown in a position intermediate and spaced fromcontacts 51 and 62 for clearness of illustration.' One end of a spiralspring 602 is also secured to the shaft GM and the other end thereof issecured at 603 to the base 604 upon which the elements of theswitch aremounted. The motor is adapted to rotate in the direction of the arrow Aagainst the resistance ofiered by spring 602 to urge arm 53 inengagement with contact 51. When power is cut off to motor 60, spring602 rotates shaft 60| in the opposite direction until arm 53 engagescontact 62. The arm 53.,

obviously, is insulated from shaft 60|- because it torque suflicient torotate the arm 53' from contact 62 to 51, spring 602 being designed inaccordance with the torque developed to limit said rotation to thedesired extent and to return the arm to its original position when thepower supply to the motor is interrupted.

It is to be understood that equivalent mechanisms may be employed toperform the same function as motor-operatedswitch 54 such, for

example, as a delayed relay or other suitable, electrical device and,therefore, I do not wish to be explained. The arm 66, however, isadaptedlimit this element of my invention to the exact means disclosed;

One terminal of motor 60 is connected by conductor 64 to conductor 34which is connected through conductor I3 to line 9 of the service mains.The other terminal of motor 60 is connected through conductor 65 to thearm 88 of a switch 61, the operation of which will hereinafter nectedthrough conductor I2 to leg 2 which, in

turn, is connected to line 8 of the service mains. It will be evident bytracing the above circuit of motor 60 that with the armatures of relayII in their normal positions, as illustrated, the motor 60 is connecteddirectly across the service mains 8 and 9. Hence, motor 60 is normallyenergized and projection 6| urges arm 53 in engagement with contact 51thereby closing the circuit to relay 3I. Assuming, however, that thepower supply fails in the mains 8 and 9, motor 60 breaks the circuit torelay 3| and connects bell 43 in the telephone. circuit.- Hence, theemission of an audible signal is effected in the event a. power failureoccurs in the visual signaling or incandescent lamp circuit.

A still further contingency, however, must be considered and that is afailure of the incandescent lamp. In the event the lamp is burned out orremoved there will be no current flow through the circuit. Thiscondition, of course, would not be apparent if, for exampla'switch 4were open. The relay II is therefore adapted upon an energizationthereof to interrupt the normal circuit connecting the motor 80 acrossthe mains 8 and 9 and to connect the same in series with the lamp I.This is accomplished by means of the fourth armature I3 of relay II towhich is attached. the conductor 69 forming a part of one leg,hereinbefore described, of the motor circuit. Inasmuch as conductor 69is connected to both armature I0 and 13, the circuit through conductor12 will be broken by armature 10 upon an energization of relay II andarmature I3 will engage a contact 14. A conductor I5 connects contact I4with conductor I. Hence, when the armwere burned out or removed or thelamp circuit.

atures of relay II are picked up, armature I3 thereof connects motor60in series with the in candescent lamp I, the filament of whichcompletes the motor circuit. The motor 60, however, does not consumesuificient, current to cause incandescence of the lamp. Obviously,'iflamp I defective, motor '60 would be unenergized thereby opening thecircuit to relay 3| and completing the bell circuit through itsactuation of the contact arm 53. From the foregoing it is apparent thatmy device is designed and adapted to prosaid lamp and in parallel withmotor I50. Hence,

when a direct circuit to the lamp is completed through the bimetallicarm 22, motor 60 is shunted. The spring 602 of the motor, however, isdesigned slowly to return arm 53 and the time required thereby to rotatesaid arm fromconvlamp circuit to line 8 of the service mains.

tact 51' to contact 82 is predeterminately fixed at an interval greaterthan that during which the bimetallic arm 22 maintains the motorshunted.

Hence, though the current intermitting device I! operates to produce anintermittent illumination of lamp I, motor 60 will not be deenergized asuflicient length of time to effect an operation of the bell. I

As hereinbefore stated, it is desirable to continue the emission of thevisual signal after an initial operation thereof is effected in responseto a flow of signaling current in the telephone lines. This isaccomplished by means ofa locking interconnection between relay II andthe transformer 36. A conductor 16 connects a-fixed contact 11- of athermostatic switch, indicated generally at 18 with conductor 29 whichleads to one terminal of the primary winding of transformer 26.-Disregarding for the moment the function of thermostatic switch 18 andassuming that contact 11 is in its normal position in engagement with amovable contact 19, a circuit is completed through said switch fromcontacts 11 and I9 through the arm thereof with which contact I9 iselectrically connected, to terminal 8| of the switch. Terminal 8| isconnected through conductor 82 to a contact 83 of relay II. This circuitconstitutes a locking circuit for the relay II. Assuming relay 3I isenergized and connects the primary 2! of transformer 26 directly acrossthe mains8 and 9; relay II will be energized through the secondary 25thereof.

Upon an energization of relay II, armature I2 lighting circuit to lamp Ias hereinbefore described. Armature I2 also serves to establish theabove described circuit. In other words, an energization of relay IIcauses armature I2 to engage contact 23. Current, therefore, flows fromline 9 of the service mains through conductors -13, armature I2 andcontact 83, conductor 82, switch arm 80, contacts 19 and TI, conductorsI8 and 29, primary winding .21 of transformer 26, conductor 28 and leg 2of the It is evident that, inasmuch as armature I2, when in engagementwith contact 83, connects transformer 26 across the mains 8 and-9 andthe secondary of the transformer feeds the coil of relay II, said-relaywill continue to be energized when and after the armature is once pickedup. Hence, a momentary operation of relay 3| in response to anenergization of the telephone mains effects a continued operation of thevisual signaling circuit.

In order to effect a discontinuance of the visual signal-emission, Ihave provided the thermostatic switch I8 which is adapted to limit theoperation of the signaling circuit to a predetermined time interval. Inthe embodiment illustrated, however, the switch 18 is designed andadapted to perform a double function. As illustrated, switch 18 isadapted after a first prede termined time interval of operation of thesignaling circuit to connect the bell in the telephone circuit and aftera further interval of time to interrupt both the audible and visualsignaling circuits and to restore the normal electriclighting circuit.

The thermostatic switch I8, as hereinbefore partially described,comprises terminal 8I to which is connected in electrical engagement abimetallic arm 8|). A wire 84 of suitable ohmic resistance is coiledaround and insulated from arm 80, one end of the coil being connected toterminal 8I and the other end connected through conductor 85 toconductor 28. Am 80 bears an insulating block 86 which is adapted toengage arm 66 of a second switch 61 hereinbefore described.

The resistance coil 84 is designed to radiate sufficient heat to causebimetallic arm 88 to warp a predetermined distance during apredetermined time interval. The switch is so designed that a movementof arm 80 upwardly, as viewed in the drawing, will first move arm 66,through the medium of block 86, away from contact 68 and thereafterdisengage contacts 11 and 19.

It will be noted that when armature I2 of relay II is operated toconnect transformer 26 across the mains 8 and 9, said armature alsoconnectsresistance coil 84 across the mains in parallel with the primarywinding of the transformer. The circuit of the resistance coil comprisesconductor I3, armature I2 and contact 83, conductor 82, terminal 8|,resistance coil 84, conductors 85 and 28 and leg 2 of the lightingcircuit. Hence, when transformer 26 is energized coil 84 is alsoenergized and aftera predetermined interval'of time depending upon theresistance of the coil, bimetallic arm '80 commences to warp. It will beremembered that when transformer 26 and coil 84 are connected incircuit, the motor of switch 54 is connected in series with lamp Ithrough switch,arm 66 and contact 68 of switch 61. Hence, when arm 88 ofswitch 18 has moved a predetermined distance switch 61 is .openedthereby opening the circuit to motor 69. With motor 60 unenergized, arm53 of switch 51 is allowed to engage contact 62 thereby connecting bell43 in the telephone circuit. At this point both the lamp signalingcircuit, that is, the cir cuit including the current intermitting deviceI1 in series with lamp I, and the bell circuit are es- 40 tablished anda simultaneous visual and audible signal emission is effected. v

After opening switch 61, the bimetallic element or arm 86 continues towarp until contacts 11 and 19 are disengaged. When this occurs, one 45leg of the circuit to the primary of transformer 26 is opened. Said legincludes conductor I3, armature I2 and contact 83 of relay I I,conductor 82, terminal 8|, bimetallic element 88, contacts 11 and 19 andconductors 16 and 29. A separa- 50 tion, therefore, of contacts 11 and19 opens the circuit to the primary of transformer 26 and relay IIbecomes deenergized thereby interrupting the circuit through the currentintermitting device and lamp I and restoring the normal light- 55 ingcircuit. This operation of relay I I, of course, reconnects themotor 60of switch 54 across the service mains 8 and 9. 4 The foregoingillustrates the means I have employed which is adapted automatically tolimit 60 the time interval of operation of the lamp signaling circuit. Ihave also provided means operable when the telephone talking circuit isclosed to interrupt the operation of the signaling circuit. This meanscomprises a relay 81, the coil of which is connected through conductors88 and 89 to terminals 35 and 31, respectively, of the subscriber'sstation. An induction cofl 98 is connected between terminals 35 and- 4|and aconduetor 9| connects terminal 4| with one contact 92 of thetelephone hook switch indicated genorally at 93. The hook 94 isconnected through conductor 95 to one terminal of the transmitter 96 andthe other terminal of transmitter 96 is connected through conductor 91to terminal 39' 77 and the telephone trunk line 39 as illustrated. v

Hence, when the receiver 98 is removed from its hook 94, as illustrated,the talking circuit will be closed and it will be seen by tracing thecircuit of relay 81 that it will be energized. The circuit is asfollows, starting from trunk line 39 6 and terminal 39'; conductor 91,transmitter 96, conductor 95, hook 94 and contact 92 of hook switch 93,conductor 9|, terminal 4|, induction coil 90, terminal 35, conductor 88,relay 81, conductor 89 and terminal 31 to which trunk line 48 isconnected. An energization of relay 81 causes the armatures 99 thereofto engage contact I00. Armature 99 and contact I08 are connected throughconductors Illl and I02, respectively, to conductors 24 and 2 whichconnect the relay II to the secondary of transformer 26. An operation,therefore, of relay 81 short circuits the secondary of transformer 26thereby rendering the relay II inoperative. Hence, when the subscriberanswers the flashing lamp signal by removing the telephone receiver,relay 81 is energized thereby effecting a discontinuance of the lampsignaling circuit and the reestablishment of the normal lightingcircuit.

From the foregoing description of ,nrv invention in its preferred form,it is evidentthat a visual signal may be efiected in response to anenergization of a telephone circuit, or, at the will of the subscriber,an audible signal or a simultaneous emission of both types of signalsmay be efiected. As hereinbefore disclosed, the visual signal transpireswhen the unlighted lamp I is intermittently illuminated or thesteadyilluminationof the lamp ceases and an intermittent illuminationthereof occurs. Furthermore, this visual signal is maintained for adefinite interval of time after which an audible signal is produced andthereafter, the operation of both sige naling devices is automaticallyterminated. If, on the other hand, the signal is answered by thesubscriberin due time, the closing of the telephone circuit efiects adiscontinuance of the signaling device or devices in the same manner asthe bell is silenced in the present telephone systems by a lifting ofthe receiver. In addition, my invention, though employing a separatesource of supply for the incandescent lamp from that supplying thetelephone circuit, insures, through the medium of the motor-operatedswitch 54, an operation of the bell in the event the lamp failsto-function or its circuit is defective'. Thislatter feature of myinvention is very desirable inasmuch as the maintenance of a continuousand uninterrupted service is of prime importance where telephonecircuits and apparatus are concerned.

It is to be understood that I not limited to the various electricalmeans illustrated and described as incorporated in the circuits of myinvention nor to the-precise circuits disclosed in order to form anoperative device of the character described, but equivalent means andcircuits may be substituted for those illustrated with comparableresults. While I have, there-. fore, described my invention in its'preferred embodiment, it is to be understood that the specific meansdisclosed together with the. ar-

rangement of the circuits embodying the same are merely illustrative andthat the words which- I have used are clescri ntivev rather than limitative. Hence, changes within the purview of the appended claims may bemade without departing from the true scope and spirit of my inven-' tionin its broader aspects.

What I claim is:

10 said first mentioned means in series therewith;

whereby upon a failure of operation of said visual signal said firstmentioned means will close the circuit to said audible device.

2. In a telephone system, a first electric cir- 15 cuit comprisingtelephone trunk lines and an audible signaling device connectibletherewith, a second electric circuit including a visual signaling deviceand means for maintaining said audible device in open circuit butoperable upon a failure of current flow therethrough to include the samein said first circuit, means connected in said first mentioned circuitand operable upon an energization thereof for controlling said visualdevice and connecting said first mentioned means in series therewith,and means for maintaining said controlled second circuit.

3. In a telephone system, a first electric circuit comprising telephonetrunk lines and an audible signaling device connectible therewith, asecond electric circuit including a visual signaling device and meansfor maintaining said audible device in open circuit but operable upon afailure of current fiow therethrough to include the same in said firstcircuit, means connected in said first mentioned circuit and operableupon an energization thereof for controlling said visual device andconnecting said first mentioned means in series therewith, and means formaintaining said controlled second circuit during a predeterminedinterval of time.

4. In a telephone system, a first electric circuit comprising telephonetrunk lines and, an audible signaling device connectible therewith, asecond electric circuit including a visual signaling device and meansfor maintaining said audible device in open circuit but operable upon afailure of current flow therethr'ough to include the same in said firstcircuit, means connected in said first mentioned circuit andoperable-upon an energization thereof for controlling said visual deviceand connecting said first mentioned means in series therewith, means formaintaining said controlled second circuit, and automatic means forterminating said maintained second circuit after a predeterminedinterval of time.

5. In a telephone system, a first electric circuit comprising telephonetrunk lines and an audible signaling device connectible therewith, asecond electric circuit including a visual signaling device and meansfor maintaining said audible device in open circuit but operable upon afailure of current flow therethrough to include the same in said firstcircuit, means connected in said first mentioned circuit and operableupon an energization thereof for controlling said visual device andconnecting saidfirst mentioned means in series therewith, means formaintaining said controlled second circuit, and means connected in saidfirst mentioned circuit for efa second electric circuitincluding avisual sig 7,

aovaeec naling device and means normally energized by said circuit formaintaining said audible signaling device in open circuit butoperableupon a failure of current fiow therethrough to include saidaudible device in said first circuit, and means connected in said firstmentioned circuit and operable upon an energization thereof foreffecting a series circuit through said first mentioned means and saidvisual signaling device.

7. In a telephone system, a first electric circuit comprising telephonetrunk lines and an audible signaling device connectible therewith, asecond electric circuit including a visual'signaling device, a switch, anormally open shunt circuit around said switch and means for maintainingsaid audible device in open circuit, and means connected in said firstmentioned circuit and operable in response to an energization thereoffor opening the circuit through said switch and closing said shuntcircuit; said first mentioned means being operable upon a failure ofoperation of said visual signal to close the circuit to said audibledevice.

8. In a telephone system, a first electric circuit comprising telephonetrunk lines and an audible signaling device connectible therewith,

a second electric circuit including a visual signaling device, a switch,a normally open shunt circuit around said switch and means formaintaining said audible device in open circuit but operable upon afailure of current fiow there-- cuit comprising telephone trunk linesand an audible signaling device connectible therewith, a

second electric circuit including a visual signaling means connected insaid first mentioned circuit and operable in response to an energizationthereof for opening the circuit through said switch and closing saidshunt circuit, means for maintaining the open circuit through saidswitch and the closed shunt circuit, and means for determining themaintained circuits.

10. In a telephone system, a first electric circuit comprising telephonetrunk lines and an audible signaling device connectible therewith, asecond electric circuit including a visual signaling device, a switch, anormally open shunt circuit around said switch and means for maintainingsaid audible device in open circuit but operable upon a failure ofcurrent flow therethrough to. include said audible device in said firstcircuit, means connected in said first mentioned circuit and operable inresponse to an energization thereof for opening the circuit through saidswitch and closing said shunt circuit, means for maintaining the opencircuit through said switch and the closed shunt circuit, and automaticmeans for determining said maintained circuits after a predeterminedinterval of time.-

11. In a telephone system, a first electric circuit comprising telephonetrunk lines and an audible signaling device connectible therewith, asecond electric circuit including a visual signaling device, a switch, anormally open shunt circuit around said switch and means for maintainingsaid audible device in open circuit but operable upon a failure ofcurrent fiow therethrough to include said audible device in said firstcircuit,- means connected in said first mentioned circuit and operablein response to an energization thereof for opening the circuit throughsaid switch and closing said shunt circuit, means for maintaining theopen circuit through said switch and the closed shunt circuit, and meansconnected in said first mentioned circuit for effecting a termination ofsaid maintained circuits.

12. In a telephone system, a first electric circuit comprising telephonetrunk lines and an audible signaling device connectible therewith, asecond electric circuit including a visual signaling device, a switch, anormally open shunt circuit around said switch, means normally energizedby said circuit for maintaining said audible signaling device in opencircuit but operable upon a failure of current fiow therethrough toinclude said audible device in said first mentioned circuit, and meansconnected in said first mentioned circuit and operable upon anenergization thereof for opening the circuit through said switch,closing said shunt circuit and effecting a series circuit through saidfirst mentioned means and said visual signaling device.

13. In a telephone system, a first electric circuit comprising telephonetrunk lines and an audible signaling device connectible therewith, asecond electric circuit including an incandescent lamp and a currentintermitting device connectible therewith, means connected in saidsecond circuit for maintaining said audible ,signaling device in opencircuit but operable upon a failure of current fiow therethrough toconnect the same in said first mentioned circuit, and means connected insaid first mentioned circuit and operable in response to an energizationthereof for connecting said current intermittlng device in said secondcircuit and connecting said first mentioned means in series with saidlamp.

14. In a telephone system, a first electric circuit comprising telephonetrunk lines and an audible signaling device connectible therewith, asecond electric circuit including an incandescent lamp, a switch, anormally open shunt circuit around said switch having a currentintermitting device connected therein, means connected in said secondcircuit for maintaining said audible signaling device in open circuitbut operable upon a failure of current fiow therethrough to coni nectthe same in said first mentioned circuit, and

means connected in saidfirst mentioned circuit and operable in responseto an energization thereof'for opening the circuit through said switchand closing said shunt'circuit.

15. In a telephone system, a first electric circuit comprising telephonetrunk lines and an audible signaling device connectible therewith, asecond electric circuit including a visual signaling device and meansfor maintaining said audible signaling device in open circuit butoperable upon a failure of current fiow therethrough to connect the samein said first mentioned circuit, means connected in said first mentionedcircuit and operable in response to an energization thereof forcontrolling said visual signaling device, and timing means operableafter a predetermined interval of controlled operation of said visualdevice for connecting said audible device in said first circuit.

- 16; In a telephone system, a first electric circuit comprisingtelephone trunk lines and an audible signaling device connectibletherewith, a second electric circuit including a visual signaling deviceand means for'maintaining said audible signaling device in open circuitbut operable upon a failure of current flow therethrough to connect thesame in said first mentioned circuit,

'means connected in said first mentioned circuit and operable inresponse to an energization thereof for controlling said visualsignaling device, and means operable after a first predetermined timeinterval of controlled operation of said visual device for aiiecting anoperation of said audible device and operable after a second,predetermined time interval for terminating the operation of bothsignaling devices. I

17. In a telephone system, a first electric circuit comprising telephonetrunk lines and an audible signaling-device connectible therewith, asecond electric circuit including an incandescent lamp, a currentintermitting device and means for maintaining said audible signalingdevice in open circuit but operable upon a failure of current flowtherethrough to connect the same in said first mentioned circuit, meansconnected in said first mentioned circuit and operable in response to anenergization thereof for con-' ,necting said first mentioned means inparallel with said intermitting device and in series with said lamp,means for maintaining said series and parallel connections, and timingmeans operable after predetermined intervals of time respectively foropening the circuit through said first mentioned means and effecting adiscontinuance of said maintained circuit.

18. Ina'telephone system, a first electric circuit comprising telephonetrunk lines and an audiblesignaling device connectible therewith, a

. said audible signaling device and means for determining the operationof said audible signaling device and the controlled operation of saidvisual signaling device.

19. In a telephone system, a first electric circuit comprising telephonetrunk lines and an audible signaling device connectible therewith, asecond electric circuit including a visual signaling device and meansfor maintaining said audible device in open circuit but operable upon afailure of current flow therethrough to connect the same in said firstcircuit, means'connected in said first circuit and operable in responseto an energization thereof for controlling said visual signaling device,means, for maintaining the controlled operation of said visual device,timing means connected in said second circuit and operable after afirst, predetermined time interval of operation of said visual devicefor connecting said audible device in said first circuit and operableafter a second, predetermined time interval for determining theoperation of both signaling devices and means connected in.said firstcircuit for determining the operation of said signaling devices.

circuit whereby an independent or joint operation of said signalingdevices is effected.

21. In a telephone system comprising a subscribers station, thecombination with an audible signaling device, a visual signaling deviceand manually controlled means for selecting and operatively associatingeither of said signaling devices with the telephone circuit foroperation in response to the flow of signaling current therein, of meansconnected in series with said visual signaling'device and operable upona failure of said visual device when it has been selected for operationfor effecting an operative association of said audible device with saidcircuit.

22. In a telephone system comprising a subscribers station, thecombination with a bell, an incandescent lampand manually controlledmeans for selecting and operatively associating either said bell or lampwith the telephone circuit for operation in response to the flow ofsignaling current therein, of means connected in series with said lampand operable when said lamp has been selected and upon a failure ofillumination thereof when signaling current flows in said telephonecircuit to effect an operative association of said bell with saidcircuit.

ANTHONY J. PARISSI.

